Microcrystalline cellulose finds widespread use as a pharmaceutical excipient because it possesses desirable compressibility characteristics. Microcrystalline cellulose is a purified, partially de-polymerized cellulose that is prepared by treating alpha cellulose, in the form of a pulp manufactured from fibrous plant material, with mineral acids. It is a white, odorless, tasteless, relatively free flowing powder that is insoluble in water, organic solvents, dilute alkalis and dilute acids. U.S. Pat. No. 2,978,446 issued to Battista et al. and U.S. Pat. No. 3,146,168 issued to Baftista describe microcrystalline cellulose and its manufacture; the latter patent concerns microcrystalline cellulose for pharmaceutical applications. Both are incorporated herein by reference in their entirety.
Unfortunately, microcrystalline cellulose is relatively costly to manufacture. This limits its use in price-sensitive formulations like vitamins and nutritional supplements. Thus, a lower cost replacement that has tabletting characteristics similar to those of microcrystalline cellulose is desired.
One solution is proposed by U.S. Pat. No. 5,585,115, which describes a particulate agglomerate of microcrystalline cellulose and from about 0.1-20% silicon dioxide. Another solution is proposed by U.S. Pat. No. 4,744,987, which describes a particulate co-processed microcrystalline cellulose and calcium carbonate in a ratio of 75:25 to 35:65.
Although these proposed solutions may be cheaper than simply using microcrystalline cellulose alone, each still requires a major amount of microcrystalline cellulose. Thus, there is still a need for a product that is suitable for tabletting and that has acceptable compressibility characteristics but contains less microcrystalline cellulose than the co-processed microcrystalline cellulose products in the prior art.
The present invention solves that need by providing a composition that includes three components: a botanical plant, microcrystalline cellulose, and calcium carbonate, a that are co-processed in a manner that produces a particulate product having unexpectedly good performance characteristics, but contains a minor amount of microcrystalline cellulose. For example, the product provides excellent compressibility, flow properties, and rapid disintegration.
Moreover, the composition of the present invention eliminates the need for wet granulation.